This project is designed so that the co-principal investigators of DA 000-55 (formerly MH 188-18), "Evaluation of an Adolescent Drug Education Program," may carry out those analyses of adolescent drug-use survey data gathered under DA 000-55 which were beyond the research purpose of that grant. These data, gathered from 13,659 junior and senior high school students and 308 school drop-outs over a three-year period according to a random, multiple-sample design, include drug-use, demographic, and attitudinal information representing a total population of 33,180 Greater New Haven youths. The purpose of the original survey was to assess the effectiveness of school drug education programs. The purpose of the proposed study is to: 1) analyse trends in incidence and prevalence of the reported adolescent drug use for the years 1970-1973, 2) analyse sequential patterns of multiple drug-use, and 3) examine, according to multivariate procedures, some of the demographic, familial, peer, and attitudinal correlates of drug use. These analyses will not only replicate research conducted in order parts of the U.S. and foreign countries but will introduce analytic techniques which are unique in the drug literature. These include more adequate measures of incidence and prevalence of drug use than have been reported elsewhere, a unique associational, scalogram, and time sequence analysis of multiple-drug use patterns, and multivariate "causal" analysis of drug use correlates. Since the data for these analyses were gathered from a reasonably typical and comprehensive school population in a representative community according to good standards of survey research, the results should be more easily generalized to other U.S. populations than results of studies which have been conducted on more limited populations.